ADVERTISEMENT
Current Trends in Charcot Reconstruction: What You Should Know
Charcot reconstruction continues to be an ever-evolving specialty in foot and ankle surgery. The basics of Charcot reconstruction aim to create a functionally braceable, plantigrade foot for ambulation, avoiding morbidity including chronic ulcer, pain and the risk of limb loss. One may accomplish this via internal or external fixation, and there are numerous studies supporting both in the literature. In this article, we will review multiple surgical approaches and techniques for Charcot reconstruction that aim to achieve these goals.
Considering Internal Versus External Fixation
In comparing the types of fixation used for Charcot reconstruction, there are several pros and cons for each. The most prominent benefit of using external fixation is that one can use this method in the presence of an infection. Additionally, there is less soft tissue dissection involved, and the patient can maintain some level of weight-bearing in a frame. A substantial con with external fixators is the postoperative care/adherence needed from the patient and the steep learning curve that exists for surgeons. The ideal construct would have both external and internal fixation to increase multiplanar stability and rigid immobilization.1
Grant and colleagues, in their 2007 publication, looked at seven different constructs on cadaver and polyurethane foam models comparing internal to external fixation, as well as combinations of both.1 They found that an external frame without tension had the least amount of compression; however, an external fixator with tension provided the best means of compression across a midtarsal arthrodesis site. The frame with tension, compression, and two 4.0 mm screws provided the best fixation overall.1 The above information is helpful when planning a midfoot Charcot reconstruction for a patient with an active infection, as an external fixator with tension will provide superior compression at the midtarsal osteotomy site without risking hardware failure secondary to internal fixation placed across infected bone.
Important Concepts Regarding Beaming in Charcot Reconstruction
William P. Grant, DPM popularized the concept of beaming in Charcot,2 and subsequent modification and perfection continues through more recent literature.3 Beaming the medial column with large diameter screws was first mentioned at the American College of Foot and Ankle Surgeons conference in 1997.4 Since then, literature supports 2 to 3 beams in the medial and lateral columns, and the hindfoot for more stability.2 Beaming the midfoot and hindfoot acts like reinforcement rods, or rebar, to accept compressive and tensile loads and compensate for inadequacies of native structures.
Grant and colleagues looked at beaming of the medial column only versus medial and lateral with and without subtalar joint arthrodesis.2 They found that with medial column beaming alone, the mechanical advantages of the posterior tibial tendon increased, which led to increased plantar lateral pressure and collapse of the non-beamed lateral column. They also found that locking the subtalar joint (via either arthrodesis or arthroereisis) further stabilized transverse and frontal plane torsion.2 Other studies confirmed that this 3-beam construct seems to be the most stable, with less chance of a secondary collapse in the foot.3,5 Other advantages of beaming include no cortical stress on the bone (unlike plates/screws), allowing for fixation beyond the site of collapse, making it more stable, and no exposed hardware in the presence of dehiscence.3
Regarding weight-bearing, studies with patients in an external fixator with beaming were allowed to walk, but those without an external fixator underwent non-weight-bearing for 2 to 3 months. Solid stainless steel screws are the strongest construct, as they provide more tensile strength than titanium. Furthermore, most studies involving beaming additionally perform an adjunct Achilles or gastrocnemius lengthening procedure for equinus, a common concomitant issue in feet with Charcot changes.3
Pertinent Points To Know About Gradual Hexapod Correction
Several studies look at a two-stage approach for Charcot reconstruction, with the first stage consisting of gradual correction via a computer-assisted hexapod.5,6 The second stage of the reconstruction occurs when one achieves the proper alignment of a plantigrade foot and usually implements rigid internal fixation. The gradual correction takes place via ligamentotaxis or a midfoot osteotomy. The hexapod has a stationary base that connects to a moving platform via six struts.
The surgeon can then make the necessary adjustments in all three axes simultaneously in accordance with the computer program. After achieving correction, one usually leaves the external fixator on for an additional 4 to 6 weeks, then removes it for internal fixation. In our experience and observation, the hexapod is one of the safest and most effective approaches to Charcot reconstruction and is used even in the presence of a foot ulceration. Other benefits include that the patient may weight-bear earlier, may experience less disuse osteoporosis, and there is access to soft tissue for wound care if indicated. The ease of computer programming has made hexapod technology readily available and a beneficial tool to have when tackling Charcot reconstructions with severe, chronic deformities.
Employing Distal Tibial Lengthening for Loss of Bone Height
A common problem in ankle/rearfoot Charcot cases is loss of height from the talus and/or chronic osteomyelitis of distal tibia and/or talus. Significant limb height loss does not leave many options for treatment, and, in our experience, patients typically poorly tolerate a limb length loss of more than 2.0 to 2.5cm. In these instances, one can generally use a vascularized fibular graft versus an ipsilateral pedicle fibular transfer, or perform Ilizarov distraction osteogenesis. The latter has shown to be advantageous when dealing with massive segmental bone defects in Charcot arthropathy or infection, allowing for soft tissue defect, infection complication management and angulation management externally within a frame.7
Although there are reports in the literature on distal tibial lengthening spanning a wide range of lengths, not all of these discussions focus on Charcot.8 In the case of limb height loss, specifically from the talus due to Charcot avascular necrosis, the best option is to fuse the tibia to the calcaneus and lengthen the distal tibia, in our observation. Surgeons can accomplish this simultaneously using external fixator that causes compression and tension at the fusion site and has struts at the distal tibia that help lengthen. We find talar loss necessitating a tibial-calcaneal fusion usually has an average loss of height of 4 cm. The correction would then be 3 cm of lengthening (subtract 1 cm for the fusion). Generally, there is a latency period of 7 to 10 days after tibial osteotomy, and then lengthening of 1 mm/day (any more length could cause neurovascular compromise).
Additional Considerations Surgeons Should Keep In Mind
Cierny, Cook, Mader, and team suggested avoiding long-term antibiotics during distal tibial lengthening due to Ilizarov’s statement that, “Osteomyelitis burns in the fire of regeneration.”9 Additionally, Sakurakichi and colleagues suggested that increased blood flow is an important factor for eradicating infection and achieving fusion in these cases.10
A general criterion for ankle fusion versus ankle joint distraction is ankle joint range of motion.7 If there are 30 degrees of motion or more, then one can attempt distraction arthroplasty in a frame for 12 weeks. A vital technique pearl is to add a talar wire in the ankle fusion to protect the STJ compression. A fibular osteotomy is necessary to prevent tethering and angular deformity at the tibial lengthening sites. The surgeon performs the tibial osteotomy by redrilling the tibial cortex with a 4.8mm drill in the same plane and finishing the osteotomy with a 5 mm osteotome.
The total time for bony consolidation is then 1.5 to 2 months per cm of lengthening. The average amount of lengthening is approximately 5.5cm. The fusion, on average, takes 4 to 6 months for complete bony healing, and the average length of frame time is 8.4 months.7
While in the frame, weight-bearing as tolerated is encouraged unless the patient is neuropathic, however, which applies to many patients with Charcot arthropathy. In our experience, these patients tend to break wires and cause pin site trauma when walking in their frames.
Concluding Thoughts
Overall, there is no one proven way to best perform Charcot reconstructions, and literature currently supports many different pathways for fixing them. In general, this article addressed the following concepts:
• external and internal fixation combined are superior to either alone;
• beaming is a preferred internal fixation of choice for Charcot patients;
• gradual correction via hexapod is likely the safest procedure; and
• distal tibial lengthening helps accommodate Charcot loss of limb height and helps with fusion of the ankle arthrodesis site.
Dr. Lee is a Fellow of the Salt Lake Regional Foot and Ankle Reconstructive Limb Salvage Fellowship in Salt Lake City, Utah. She is an Associate of the American College of Foot and Ankle Surgeons.
Dr. Clark and Dr. Seegmiller are the Fellowship Directors of the Salt Lake Regional Foot and Ankle Reconstructive Limb Salvage Fellowship in Salt Lake City, UT. They are both Fellows of the American College of Foot and Ankle Surgeons.
Dr. Hronek is faculty at the Salt Lake Regional Foot and Ankle Reconstructive Limb Salvage Fellowship in Salt Lake City, UT. She is a Fellow of the American College of Foot and Ankle Surgeons.
1. Mechanical testing of seven fixation methods for generation of compression across a midtarsal osteotomy: a comparison of internal and external fixation devices. J Foot Ankle Surg. 2007;46(5):325–335 Available at: https://doi.org/10.1053/j.jfas.2007.05.010. 1.
2. Grant WP, Garcia-Lavin S, Sabo R. Beaming the columns for Charcot diabetic foot reconstruction: A retrospective analysis. J Foot Ankle Surg. 2011;50(2):182–189. https://doi.org/10.1053/j.jfas.2010.12.002.
3. Conway C, Shaheed N. Medial and lateral column beaming: A literature review. Podiatry Institute 2017 Update. Available at: http://www.podiatryinstitute.com/pdfs/Update_2017/Chapter37_final.pdf .
4. Grant WP Biomechanics of the Charcot foot collapse and roding the medial column of the foot as a beam to salvage the Charcot foot. Annual American College of Foot and Ankle Surgeons Scientific Seminar. Orlando, FL. 1997.
5. Lamm BM, Gottlieb HD, Paley D. A two-stage percutaneous approach to Charcot diabetic foot reconstruction. J Foot Ankle Surg. 2010;49(6):517–522. https://doi.org/10.1053/j.jfas.2010.07.014.
6. Wrotslavsky P, Kriger SJ, Hammer-Nahman SM, Kwok JG. Computer-assisted gradual correction of Charcot foot deformities: An in-depth evaluation of stage one of a planned two-stage approach to Charcot Reconstruction. J Foot Ankle Surg. 2020;59(4):841–848. https://doi.org/10.1053/j.jfas.2019.06.008.
7. Tellisi N, Fragomen AT, Ilizarov S, Rozbruch SR. Limb salvage reconstruction of the ankle with fusion and simultaneous tibial lengthening using the Ilizarov/Taylor Spatial Frame. HSS J. 2008;4(1):32-42. https://doi.org/10.1007/s11420-007-9073-0.
8. Ali A, Zhou C-H, Fang J, Qin C-H. Unprecedented tibial bone lengthening of 33.5 cm by distraction osteogenesis for the reconstruction of a subtotal tibial bone defect. a case report and literature review. BMC Musculoskelet Disord. 2021;22(1):88. https://doi.org/10.1186/s12891-021-03950-1
9. Kovoor CC, Padmanabhan V, Bhaskar D, George VV, Viswanath S. Ankle fusion for bone loss around the ankle joint using the Ilizarov technique. J Bone Joint Surg Br. 2009;91(3):361-366. https://doi.org/10.1302/0301-620x.91b3.20935.
10. Sakurakichi K, Tsuchiya H, Uehara K, et al. Ankle arthrodesis combined with tibial lengthening using the Ilizarov apparatus. J Orthop Sci. 2002;8:20–25.
Additional References
11. Ilizarov S, Rozbruch R, Blyakher A. Ankle fusion with simultaneous lengthening using the Ilizarov method. Institute for Limb Lengthening and Reconstruction, Hospital for Special Surgery. Available at: https://www.hss.edu/files/LL-Ankle-Arthrodesis-Simultaneous-Lengthening.pdf . Accessed March 2, 2022.
12. Michetti L, Fink J, Siddiqui N. Key pearls on using distal tibial distraction osteogenesis for limb length discrepancy due to Charcot. Podiatry Today. 2019:32(4). Available at: https://www.hmpgloballearningnetwork.com/site/podiatry/key-pearls-using-distal-tibial-distraction-osteogenesis-limb-length-discrepancy-due-charcot . Published April 1, 2019. Accessed March 2, 2022.
13. Rozbruch SR. Posttraumatic reconstruction of the ankle using the Ilizarov method. HSS J. 2005;1(1):68-88. https://doi.org/10.1007/s11420-005-0113-3.
